Comment by p_ing
1 day ago
> Obviously, at the time of the 80486, DDR didn’t exist, so SDRAM is a natural fit.
Neither are a fit, SDRAM was a Pentium/K-6 standard (PC66); the DIMMs ran faster than a non-OC'ed 486 bus, which ran at half the clock of the CPU. 486 "natural fit" would be FPM or EDO, if you wanted to be era-correct.
There were probably some off the wall 486 motherboards back then that supported SDR (post-1993...), but those would have been towards the very end of the 486 consumer life cycle. These did exist in the 486 era, where they had the option to run (or had an embedded) 386 using FPM while there was an open 486 socket and the option, but not requirement to run EDO.
Anyway, this is someone's project, so they can do whatever the heck they want.
Author here. You’re right—EDO or FPM would be correct for the era. But as others have noted, DDR3 is fundamentally different from early 1990s memory, and it simply won’t run at the very low clock speeds of a 486. SDRAM, on the other hand, behaves in a way that’s much more comparable to the memory used back then.